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Biomedical subjects

S Gershon

Publications and source records attributed to S Gershon.

At least 181 records · Page 10Linked to original sources
PubMed1978

Pharmacological and biochemical properties of isomeric yohimbine alkaloids.

The stereochemical and pharmacological properties of yohimbine and some of its isomers are briefly reviewed. Several pharmacological and physical properties of a selection of the isomers have been determined with a view to elucidating which might be important in the elaboration of the known behavioral effects produced by them. Activity is not dependent upon lipid solubility or on the ease of access to the central nervous system. The isomers are weak inhibitors of rat-brain acetylcholinesterase and weak antagonists at muscarinic cholinergic receptors. In the rat brain in vitro they do not possess significant monoamine oxidase-inhibiting properties nor do they inhibit the uptake of serotonin. They are relatively potent antagonists of 5HT on the rat isolated fundus preparation and their potency in this preparation may be related to their ability to produce behavioral and cardiovascular effects in man and dogs.

Animals↗
PubMed1978

The effects of hyperbaric and normobaric oxygen on cognitive impairment in the elderly.

Eighty-two elderly subjects with significant cognitive impairment were randomly assigned to treatment with either hyperbaric oxygen, hyperbaric air, normobaric oxygen, or normobaric air. Treatment consisted of two 90-minute sessions a day for 15 consecutive days. Subjects were evaluated on measures of memory and intellectual capacity, as well as on psychiatric symptom rating scales. Results immediately after treatment and at one, two, three, and eight weeks following treatment did not show enhanced cognitive functioning or significantly greater symptom reduction in experimental subjects who received either normobaric or hyperbaric oxygen as compared to controls who received hyperbaric or normobaric air. There was also no evidence of differential treatment effects as a function of initial severity of illness, sex, response to a CO2 loading test, or presumed evidence of cerebrovascular disease.

Aged↗
PubMed1978

Thiethylperazine; clinical antipsychotic efficacy and correlation with potency in predictive systems.

A one-to-one relationship between clinical antipsychotic potency and pharmacologic dopaminergic antagonism is implicit in the dopamine hypothesis of neuroleptic action. Thiethylperazine maleate, a classical antiemetic phenothiazine, displays dopaminergic antagonism in behavioral, neurochemical, and neuroendocrine systems, but is paradoxical insofar as it is thought not to possess clinical neuroleptic activity. In three tests of dopaminergic antagonism--elevation of levels of CSF homovanillic acid in monkeys, striatal dihydroxyphenylacetic acid in rats, and prolactin in man--as well as in a clinical trial of neuroleptic efficacy in schizophrenics, thiethylperazine was fully active and approximately three times as potent as chlorpromazine. Differences in efficacy between this and earlier clinical studies can be accounted for on the basis of dosage.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1978

Dopamine receptor stimulation in the treatment of depression: piribedil (ET-495).

ET-495, a putative central dopamine receptor stimulant, was givem to endogenously depressed individuals, all of whom were largely unresponsive to previous drug treatment. The drug exhibited a rapid and, in some cases, a pronounced antidepressant effect. This effect was short-lived, however, and, within a brief period, depression returned accompanied by a consistent syndrome of anger, irritability, hostility and poor temper control. In one individual with a bipolar history, the induction of a paranoid psychosis and auditory hallucinosis occurred. While the data suggests a role for dopamine in the symptomatic relief of depression in man, they also imply that this monoamine cannot, in and of itself, be considered as the primum movens in either the action of other (established) antidepressant drugs, or as underlying depressive illness.

Adjustment Disorders↗
PubMed1978

Suppression of prolactin by dopamine agonists in schizophrenics and controls.

Prolactin levels were determined in plasma samples obtained before and after administration of apomorphine or L-dopa to otherwise unmedicated chronic schizophrenic patients or control subjects. Basal prolactin levels did not differ in these two groups. Suppression of prolactin levels after each dopamine agonist was highly significant. Suppression in schizophrenics was slightly less than in controls following apomorphine and slightly greater following L-dopa. The authors discuss the implications of these findings as well as the limitations of the prolactin regulatory system as an index of dopamine agonist sensitivity.

Adult↗
PubMed1977

Dopaminergic agonist properties of ephedrine--theoretical implications.

Reports of ephedrine-induced psychoses resembling amphetamine psychosis prompted studies of this classic sympathomimetic agent in systems that indicate central dopaminergic actions. Ephedrine induced dose-related stereotyped behavior in rats. This behavior was antagonized by haloperidol, but not by alpha- or beta-adrenergic blockers. Pretreatment with AMPT, but not reserpine, attenuated the stereotypy induced by ephedrine under one of two sets of conditions. Consistent prolactin suppression in humans was not seen. These findings are discussed in the context of clinical and pharmacologic data regarding other dopamine agonist drugs (the central nervous system stimulants, apomorphine, ET 495). These data suggest the possibility that synergistic noradrenergic and dopaminergic facilitation may be important in the induction of the stimulant psychoses.

Animals↗
PubMed1977

The effect of methylphenidate on test performance in the cognitively impaired aged.

It was hypothesized that a central nervous system stimulant with relatively weak peripheral effects would facilitate test performance in the cognitively impaired aged. Twelve elderly subjects participated in a counter-balanced, crossover comparison of 10 mg methylphenidate, 30 mg methylphenidate and placebo. All treatments were administered double-blind as a single dose of oral medication. Neither dosage of active medication was found to effect psychomotor or psychological test performance, subjective report, heart rate or blood pressure. A subsequent open trial of 45 mg methylphenidate resulted in heart rate, blood pressure and subjective changes in two of eight subjects but no effects on test performance. The results suggest that cognitive performance in the moderately impaired aged is unimproved following administration of methylphenidate, and perhaps similar sympathomimetic amines, below a dosage level associated with clinically significant peripheral effects.

Aged↗
PubMed1977

Antidepressant drugs and dopamine uptake in different brain regions.

The effect of trycyclic antidepressants on 3H-dopamine uptake into synaptosomes obtained from rat striatum and mesolimbic cortical areas was examined. Chlorimipramine was found to be the most potent uptake inhibitor (IC50 of 3.2-3.8 X 10(-6) M) in both brain regions. Desmethylimipramine, protryptyline and iprindole were approximately one-half as potent (IC50 of 5.9-8.5 X 10(-6) M) in both brain areas. Kinetic constants obtained from Line-weaver-Burk plots in both areas revealed no alteration in Km for transport and a decrease in V max thus indicating a non-competitive inhibition. The effect of chlorimipramine on the release of 3H-dopamine from striatal synaptosomes required a concentration 10(-5) M for 50% release in 5 min. It is suggested that dopamine uptake inhibition may play some role in the action of tricyclic drugs, e.g., activation of schizophrenic psychopathology but that this action can not be solely responsible for their antidepressant properties.

Animals↗